Sensing How Much the Earth Moved in Nepal

On April 25, 2015, the Earth moved violently in Nepal. A magnitude 7.8 earthquake killed more than 8,000 people, injured at least 19,000, and displaced hundreds of thousands in cities and villages near the Himalayas. The quake destroyed infrastructure and homes, both modern and historic, while triggering landslides on Mount Everest, near the village of Langtang, and in several other locations around Kathmandu. The Gorkha earthquake has been called the worst natural disaster in Nepal since a magnitude 8.0 earthquake in 1934. The Gorkha earthquake changed the shape of the Earth—literally—by raising up and dropping landscapes by several meters. Along a 90 by 30 kilometer (55 by 20 mile) swath of land in Nepal, a fault along the edges of the Indian and Eurasian tectonic plates slipped as much as 6 meters (20 feet). The release of stress in Earth’s crust had devastating effects felt in Nepal, India, China, and Bangladesh. Satellite and ground-based sensors are now revealing the extent of the jolt.